考虑材料劣变的既有钢筋混凝土桥梁时变地震易损性研究

Some researches on RC bridge structures performance considering material deterioration process have been performed in China and abroad, and it has concluded that loading capacities and deformation properties of structural members decreased differently with the material deterioration process. But there are few researches about dynamic performances, which need to be strengthened. In this project, RC bridge structures during service period will be studied. This project will study chloride induced reinforcement corrosion as the main material deterioration model and build its numerical model. The material deterioration numerical model will be analyzed together with finite element model of bridge structures through introduction of self-updating unit, and finally the time-variant seismic fragility curves of bridge structures will be obtained. Then several types of existing RC bridge structures will be simulated as an example to present the time-variant seismic fragility curves. This project seeks to illustrate the affecting mechanism of material deterioration process on RC bridge structure seismic performance, and reveal the law of the decreasing of RC bridge structure seismic performance changes over time under marine environment. Research results can be part of the theoretical basis for design of new bridge structures and safety assessment and repair/reinforcement of the existing bridge structures in coastal areas, especially have significance on life-cycle cost control and whole-life design of bridge structures.

目前国内外已经在考虑材料劣变过程的钢筋混凝土桥梁结构的性能方面开展了一些研究，得出了构件承载力和变形性能随材料劣变过程发展而不同降低的结论。但对其动力性能的研究仍然很少，需要加强这些方面的研究。本项目拟以服役期内钢筋混凝土桥梁结构为研究对象，针对氯离子引起的钢筋锈蚀为主要材料劣变模型进行研究，建立材料劣变数值模型，通过引入自更新单元实现其与桥梁结构有限元模型的协同分析，进而得出桥梁结构的时变地震易损性曲线。此后以既有的某几类典型的钢筋混凝土桥梁结构为例进行数值模拟，展示不同模型桥梁结构的时变地震易损性曲线。本项目力求阐明材料劣变过程对钢筋混凝土桥梁结构抗震性能的影响机理，揭示滨海环境下钢筋混凝土桥梁结构随时间变化的抗震性能降低的规律。研究成果可为滨海地区新建桥梁结构的设计和既有桥梁结构的安全评估和维修加固工作奠定部分理论基础，尤其对桥梁结构全生命周期成本的控制和全寿命设计具有重要意义。

本项目针对考虑材料劣变过程的钢筋混凝土桥梁结构的承载力和变形性能随材料劣变过程发展而降低的情况，以服役期内钢筋混凝土桥梁结构为研究对象，针对氯离子引起的钢筋锈蚀为主要材料劣变模型进行了研究。首先建立材料劣变数值模型，通过引入自更新单元实现其与桥梁结构有限元模型的协同分析，进而得出了桥梁结构的三维时变地震易损性曲线。此后以既有的钢筋混凝土桥梁结构为例进行数值模拟，展示了不同模型桥梁结构的三维时变地震易损性曲线。本项目阐明了材料劣变过程对钢筋混凝土桥梁结构抗震性能的影响机理，揭示了滨海环境下钢筋混凝土桥梁结构随时间变化的抗震性能降低的规律。研究成果可为滨海地区新建桥梁结构的设计和既有桥梁结构的安全评估和维修加固工作奠定部分理论基础，尤其对桥梁结构全生命周期成本的控制和全寿命设计具有重要意义。